The new 130-cm optical telescope at Devasthal, Nainital

A modern Ritchey-Chretien Cassegrain 130-cm diameter optical telescope has been successfully installed at Devasthal, Nainital in the central Himalayan region. This location was chosen after carrying out extensive site surveys. The first images obtained with the telescope indicate that atmospheric seeing and sky darkness at Devasthal are nearly at values as measured during the site survey. The values of seeing and sky darkness are comparable to some of the best astronomical sites in the world. The 130-cm telescope is functional and observations can be carried out from the control centre at Devasthal or from the Manora Peak in Nainital. This telescope has started providing valuable data for a number of research projects and is expected to help meet part of the national requirement in optical observational astronomy from small-aperture ground-based telescopes

Cohesive Methodology in Construction of Enclosure for 3.6m Devasthal Optical Telescope

Building telescope enclosures is vital for setting up any optical observatory. An enclosure was constructed in remote hilly terrain to provide shelter to India’s largest 3.6 m Devasthal Optical Telescope (DOT). Primarily, the enclosure was built to protect the telescope from tough weather conditions and provide optimum space for performing various telescope related operational and maintenance activities. Other elements that were considered in the building enclosure were low thermal mass, sustainability, seismic and acoustic considerations. A steel building designed with mostly bolted connections, suitably selected materials, and mechanical systems for facilitating construction activities on site has been built for the telescope at the Devasthal site of ARIES. The enclosure construction was quite a challenging task with various project complexities. Multidisciplinary works of civil, mechanical and electrical systems in enclosure required efforts on various fronts in parallel to achieve the targets. Limitations of resources, manpower, and site conditions were managed to keep flexibility and economics in construction. Numerous challenges faced during the making of enclosures have been discussed in the paper. Insights into the construction of enclosures will provide a basic framework and learning opportunities for managing such typical construction projects in adverse weather conditions at mountainous sites. Doi: 10.28991/HIJ-2022-03-02-05 Full Text: PD

Study of atmospheric aerosols over the central Himalayan region using a newly developed Mie light detection and ranging system: preliminary results

A LIDAR system to receive Mie backscattered photons has been developed at the Manora peak, Nainital, India and it is the first of its kind in the central Himalayan region. The system is sensitive to receive backscattered photons from heights up to ~20 km (above ground level). The atmospheric extinction profiles using Mie LIDAR have been estimated for the first time at this site in January (winter) and March (spring) seasons in three campaigns and maximum values are found to be ~ 0.01, 0.03, and 0.08 km-1, respectively. The aerosol optical depth (AOD) values are found to be ~ 0.051, 0.098, and 0.233 in three campaigns, respectively, showing enhancement from January (winter) to March (spring) indicating a seasonal variation. AOD values of LIDAR, aerosol robotic network, and moderate resolution imaging spectroradiometer were found within the standard deviations. The aerosol loading at the site has increased during the last decade as evident from previous studies